Test 1

1. Given that the key is 25, with the user of Caesar cipher, encrypt the following letters (6 Marks)

1. C
2. I 
3. P 
4. H 
5. E 
6. R

 

2. The plaintext “cryptography” is converted into the ciphertext “fubswrjudskb” by using the Caesar cipher. 

a) Determine the possible key.  (4 Marks)

( 10 marks)

 

3. In a public-key system using RSA, you intercept the ciphertext C = 10 sent to a user whose public key is e = 5, n = 35. What is the plaintext M?

(10 Marks)

 

4. The OSI security architecture consist of security services, mechanisms, and attacks. Explain the security services and mechanisms.
 

Transcribed Image Text:

'7 12 201 b. Given the key, K = 5 17 22 encrypt the plaintext using the hill cipher. 4 16 21 '7 12 201 b. Given the key, K = 5 17 22 encrypt the plaintext using the hill cipher. 4 16 21